Where to Buy Sodium Hydroxide

Sodium Hydroxide

By Walkerma [Public domain], from Wikimedia Commons

Sodium hydroxide (NaOH) or lye is a common ingredient in many science projects, particularly chemistry experiments, and to make homemade soap and wine. It's also a caustic chemical, so it's not as easy to find in stores as it used to be. Some shops carry it as Red Devil lye with laundry supplies. It's also found, usually in impure form, in solid drain cleaners. Craft stores carry lye for soapmaking. There is also food-grade sodium hydroxide, sold in some specialty cooking stores.

You can find sodium hydroxide online. You can purchase it at Amazon as sodium hydroxide or lye. Pure lye drain opener, caustic soda, and pure or food grade sodium hydroxide. Depending on your project, you may be able to substitute potassium hydroxide (KOH), which has similar chemical properties and is easier to find. However, these two chemicals aren't the same, so if make the substitution, expect slightly different results.

How to Make Sodium Hydroxide

If you can't purchase sodium hydroxide, you can use a chemical reaction to make it. You will need:

  • Table salt (sodium chloride, non-iodized)
  • 2 Carbon electrodes (from zinc-carbon batteries or graphite pencil leads)
  • Alligator clips
  • Water
  • Power supply (e.g., 9-volt battery)
  1. In a glass container, stir salt into water until it dissolves. Do not use an aluminum container or aluminum utensils because sodium hydroxide will react with them and damage them.
  2. Place the two carbon rods in the container (not touching).
  3. Use alligator clips to connect each rod to a terminal of the battery. Let the reaction proceed about 7 hours. Place the set-up in a well-ventilated space, as hydrogen and chlorine gas will be produced. The reaction produces a sodium hydroxide solution. You can use it as such or can evaporate off the water to concentrate the solution or obtain solid lye.

This is an electrolysis reaction, which proceeds according to the chemical equation:

2 NaCl(aq) + 2 H2O(l) → H2(g) + Cl2(g) + 2 NaOH(aq)

Another way to make lye is from ashes.

  1. To do this, boil ashes from a hardwood fire in a small amount of distilled water for about half an hour. To get a large amount of lye requires a lot of ashes. Hardwood ash (e.g., oak) is preferable to softwood ash (e.g., pine) because softer woods contain a lot of resin.
  2. Let the ashes sink to the bottom of the container.
  3. Skim lye solution from the top. Evaporate the liquid to concentrate the solution. Note that lye from ashes is relatively impure but should be good enough for many science projects or to make soap.

To make a crude soap from homemade lye, all you need to do is combine lye with fat.

Sodium Hydroxide Projects

Once you have lye, you can use it in a variety of science projects. You can make a sodium hydroxide solution to use as a base, make homemade soap, make water glass for homemade "magic rocks", or try the gold and silver "magic" pennies experiments.